Frederick a



(No Model.)

I'. A. WALDRON. DIFFERENTIAL PULLBY BLOCK.

Patented June 2, 1896.

Noi 561,246.

UNITED STATES PATENT OEEICE.

FREDERICK A. VALDRON, OF STAMFORD, CONNECTICUT, ASSIGNOR TO THE YALE & TOWNE MANUFACTURING COMPANY, OF SAME PLACE.

DIFFERENTIAL PU LLEY-BLOCK.

SPECIFICATION forming part of Letters Patent No. 561,246, dated June 2, 1896.

l Application filed December 19, 1895. Serial No. 572,687. (No model.)

To all whom it may concern,.-

Be it known that I, FREDERICK A. WAL- DRON, a citizen of the United States, residing at Stamford, in the county of Fairfield and State of Connecticut, have invented certain new and useful Improvements in Differential Pulley-Blocks, of which the following is a specification.

My present invention relates more particularly to the double top sheave, and it is designed as an improvement upon the block known as the Veston differential pulleyblock, the top sheave of which is made in a single piece. In practice in this class of hoists the teeth of the top sheave, which form one side of the pockets on which the chainlinks rest, always wear out before the chain, consequently requiring one or more new double top sheaves before the chain is so worn as to become useless. The object of the present invention is to overcome this objection, and I accomplish it by forming the double top sheave in two parts, so that the position of the two parts of the top sheave and their pockets can be reversed, so as to bring the bearing-points of the chain upon the opposite sides of the pockets, thus increasing the wear and life of the sheave.

In order that my invention may be fully understood, I will proceed to describe the same with reference to the accompanying drawings, in which` A Figure 1 is an elevation of a pulley-block with my improved top sheave applied. Fig. 2 is a vertical section of the top sheave. Fig.

3 is a detail sectional view of a portion of the( sheave, and Fig. 4 is a horizontal section of the top sheave.

In the said drawings, l represents the double top sheave, which is journaled in the usual manner to the supporting-frame 2, of any construction and supplied with the usual chain-guard, and 3 the lower sheave, of the usual construction, which is mounted in the lifting-frame 4, also of any construction and arrangement of parts.

5 represents the chain passing over the top sheave and around the lower one, and in Fig. 3 the arrow indicates the direct-ion of pull of the chain.

In my present invention I form the double top sheave in two distinct and complete sheaves 6 7, as shown, and they are held from relative rotation by the bolts 3 and the steadypins 9. The two sheaves when thus secured form but a rigid single block which rotates upon the pin l0, carried by the frame 2. In Fig. 2 it will be seen that each sheave is formed with the holes 11 symmetrically arranged, so that when it becomes necessary to change the bearing-points for the chain it is only necessary to remove the bolts 8 and reverse either one or both of the sheaves and insert the steady-pin in the new holes presented. By this construction and arrangement it will be seen that when the teeth 12 on either sheave become worn the sheave can be taken out of the frame and reversed, so that the worn part 13 (indicated in dotted lines in Fig. 3) will be on the under side, while the new bearing surface 14 will be brought into contact with the chain, thus obviating the great objection and expense incident-to the block now in use, at the same time greatly lengthening the life and wear of the block.

It is obvious that there are various ways of connecting the two parts of the double top sheave-that is, that there might be a great variety in the methods of fastening the two parts together without departing from the spirit of my invention.

Having thus described my invention, the following is what I claim as new therein and desire to secure by Letters Patent:

1. In a differential pulley-block or hoist a double top sheave, constructed of two separate symmetrical sheaves adapted to be reversed end for end on the shaft, and means for locking the two sheaves so as to hold them from relative rotary movement on said shaft, substantially as shown and described.

2. In a differential hoist, a double top sheave formed of two reversible sheaves secured to- `gether and held from relative movement by means of steadypi11s and bolts substantially as shown and described.

3. In a differential heist or pulley-bleek, a

double top sheave formed of two sheaves symmetrieally formed and secured together by suitable means, each of said sheaves being provided with sy1nmeti'ieally-arranged open- 

